According to the miniaturization and complexity of a semiconductor device, a technique of managing a lithography or etching process by inspecting and measuring a fine pattern of about 10 nm formed on a wafer with a high degree of accuracy and at high speed is widely used in semiconductor plants in the world. In particular, a length measurement scanning electron microscope (Critical Dimension Scanning Electron Microscope: CD-SEM) is a measurement device essential to process management of a fine pattern.
In order to perform high-precision measurement by using a device such as the CD-SEM, a device condition needs to be properly set. In PTL 1, there is described a technique of determining the necessity of automatic focus adjustment (Auto Focus: AF) on the basis of the evaluation of a power spectrum high-frequency component of a SEM image. In PTL 2, there is disclosed a method of determining the necessity of axis adjustment of a charged particle beam on the basis of an image quality evaluation value of a SEM image. In PTL 3, there is disclosed a method of determining the necessity of an aberration correction on the basis of the output result of an environment sensor, or the detection results of the sharpness of images captured from a plurality of directions, in a SEM equipped with an aberration corrector. In PTL 4, there is disclosed an electromagnetic lens in which it is provided with two coils and it is possible to adjust a focusing condition while making the amount of heat generation constant, by adjusting the difference between currents flowing through both the coils, while making the sum of the currents constant.